Update composer to allow for patch versions of Laravel 5.8

Fixes #216

Author: mikebronner

composer.json

@@ -16,11 +16,11 @@
     ],
     "require": {
         "fico7489/laravel-pivot": "dev-patch-1@dev",
-        "illuminate/cache": "5.8",
-        "illuminate/config": "5.8",
-        "illuminate/console": "5.8",
-        "illuminate/database": "5.8",
-        "illuminate/support": "5.8",
+        "illuminate/cache": "5.8.*",
+        "illuminate/config": "5.8.*",
+        "illuminate/console": "5.8.*",
+        "illuminate/database": "5.8.*",
+        "illuminate/support": "5.8.*",
         "php": "^7.1.3"
     },
     "require-dev": {